>> Subject: [PATCH] PCI: Optimize bus mem sizing to small size >> >> Current code try to get min_align as possible and use that to >> align final size. >> >> That could cause generate wrong align/size or too big size in some case. >> >> when we have align/size: 16M/64M >> min_align/size0 will be 8M/64M, that is wrong, align must be 16M. >> >> when we have align/size: 1M/1M, 64M/64M, >> min_align/size0 will be 32M/96M, that is way too big for sum size 65M. >> >> That will cuase allocation fails. >> >> The patch introduce max_align/size0_max, and size0_max is just >> sum of all children resource. >> >> Prefer small size instead of small align. Only use min_align when >> two size is the same. >> >> The new size will only need to be aligned to bus window alignment. >> >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> > > I'm sorry, I can't make any sense out of this. I can't understand > what you're trying to say. > > A specific simple example might help. > > Is this a regression? Should it be marked for stable? If so, how far > back? > > It doesn't apply on v4.1-rc2 (I would apply it manually if I could > understand the changelog and comments, but you might as well refresh it at > the same time as you rewrite those). > > Please include a link to the problem report. > > Please include the patch inline in the message. It is a significant hassle > for me to deal with attachments, and you are the only major contributor who > uses them. Hi Yinghai, do you have some updates for this patch ? I open a bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100451 I hope this fix could be merged in upstream. Thanks! Yijing. > > Bjorn > >> --- >> drivers/pci/setup-bus.c | 50 +++++++++++++++++++++++++++++++++++++++++++++--- >> 1 file changed, 47 insertions(+), 3 deletions(-) >> >> Index: linux-2.6/drivers/pci/setup-bus.c >> =================================================================== >> --- linux-2.6.orig/drivers/pci/setup-bus.c >> +++ linux-2.6/drivers/pci/setup-bus.c >> @@ -882,12 +882,14 @@ static void pbus_size_io(struct pci_bus >> } >> >> size0 = calculate_iosize(size, min_size, size1, >> - resource_size(b_res), min_align); >> + resource_size(b_res), >> + window_alignment(bus, IORESOURCE_IO)); >> if (children_add_size > add_size) >> add_size = children_add_size; >> size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 : >> calculate_iosize(size, min_size, add_size + size1, >> - resource_size(b_res), min_align); >> + resource_size(b_res), >> + window_alignment(bus, IORESOURCE_IO)); >> if (!size0 && !size1) { >> if (b_res->start || b_res->end) >> dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n", >> @@ -962,6 +964,8 @@ static int pbus_size_mem(struct pci_bus >> struct resource *b_res = find_free_bus_resource(bus, >> mask | IORESOURCE_PREFETCH, type); >> resource_size_t children_add_size = 0; >> + resource_size_t max_align = 0, size0_max; >> + int count = 0; >> >> if (!b_res) >> return -ENOSPC; >> @@ -1016,19 +1020,59 @@ static int pbus_size_mem(struct pci_bus >> if (order > max_order) >> max_order = order; >> >> + count++; >> + if (align > max_align) >> + max_align = align; >> + >> if (realloc_head) >> children_add_size += get_res_add_size(realloc_head, r); >> } >> } >> >> + /* >> + * New rule: Prefer to small size instead of small align, >> + * when we have align/size: 1M/1M, 2M/2M, >> + * min_align/size0: 1M/3M, max_align/size0_max: 2M/3M >> + * pick 1M/3M. >> + * when we have align/size: 1M/1M, 64M/64M, >> + * min_align/size0: 32M/96M, max_align/size0_max: 64M/65M >> + * pick 64M/65M. >> + * when we have align/size: 1M/1M, 16M/64M, >> + * min_align/size0: 8M/72M, max_align/size0_max: 16M/65M >> + * pick 16M/65M. >> + * when we have align/size: 32M/64M, 128M/512M >> + * min_align/size0: 64M/576M, max_align/size0_max: 128M/576M >> + * pick 64M/576M. >> + * when we have align/size: 16M/32M, 128M/512M >> + * min_align/size0: 64M/576M, max_align/size0_max: 128M/554M >> + * pick 128M/554M. >> + * when we have align/size: 16M/64M >> + * min_align/size0: 8M/64M, max_align/size0_max: 16M/64M >> + * have to use 16M/64M. >> + */ >> min_align = calculate_mem_align(aligns, max_order); >> min_align = max(min_align, window_alignment(bus, b_res->flags)); >> + max_align = max(max_align, window_alignment(bus, b_res->flags)); >> + if (count == 1) >> + min_align = max_align; >> + >> size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align); >> + size0_max = calculate_memsize(size, min_size, 0, resource_size(b_res), >> + window_alignment(bus, b_res->flags)); >> + >> + if (size0_max < size0) { >> + size0 = size0_max; >> + min_align = max_align; >> + max_align--; /* to use small align for size1 calculation */ >> + } >> + >> if (children_add_size > add_size) >> add_size = children_add_size; >> size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 : >> calculate_memsize(size, min_size, add_size, >> - resource_size(b_res), min_align); >> + resource_size(b_res), >> + min_align <= max_align ? min_align : >> + window_alignment(bus, b_res->flags)); >> if (!size0 && !size1) { >> if (b_res->start || b_res->end) >> dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n", > > > . > -- Thanks! 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